JP4378792B2 - Fluid coupling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a fluid coupling device for transmitting rotational torque of a prime mover.
[0002]
[Prior art]
Fluid couplings (fluid couplings) are conventionally used as power transmission couplings for ships, industrial machines, and automobiles. The fluid coupling is a casing connected to a crankshaft (input shaft as a fluid coupling) of a diesel engine that is a prime mover, a pump disposed opposite to the casing and attached to the casing, and opposed to the pump. And a turbine attached to an output shaft disposed on the same axis as the input shaft.
[0003]
A fluid coupling provided with a lock-up clutch that frictionally engages the casing and the turbine has also been proposed between the casing and the turbine. This lock-up clutch is provided between a casing and a turbine, and includes a clutch disk that forms an outer chamber between the casing and an inner chamber between the turbine and the turbine. The casing and the turbine are configured to be frictionally engaged by a pressure difference between the inner chamber side and the outer chamber side.
[0004]
When the above-described fluid coupling is installed in, for example, a vehicle drive device, the transmission is generally connected to a manual transmission via a friction clutch, and the fluid coupling is directly connected to an automatic transmission.
[0005]
[Problems to be solved by the invention]
The above-described fluid coupling equipped in the vehicle drive device has its characteristics when the engine is driven and the transmission gear of the transmission is engaged when the vehicle is stopped, that is, when the input shaft rotates and the output shaft stops. Has upper drag torque. This drag torque becomes considerably large when the rotational speed ratio at which the design point of the fluid coupling is the maximum efficiency, that is, the rotational speed ratio between the pump and the turbine is 0.95 to 0.98. If the drag torque is large, the idling operation of the engine becomes extremely unstable, and this unstable rotation causes abnormal vibration in the drive system. In addition, the large drag torque also causes a deterioration in fuel efficiency during idling.
[0006]
In order to reduce the drag torque, it is conceivable to reduce the pressure of the working fluid that circulates through the fluid coupling. However, if the pressure of the working fluid is decreased, the filling efficiency of the fluid coupling will decrease, so the transmission torque at high revolutions will also decrease. It will decline. Further, in a fluid coupling provided with a lockup clutch, the operating pressure of the lockup clutch is insufficient, and in the worst case, the lockup is impossible.
[0007]
The present invention has been made in view of the above-described facts, and a main technical problem thereof is to provide a fluid coupling device capable of reducing drag torque without impairing the torque transmission function.
Another technical problem is to provide a fluid coupling device that can reduce the drag torque without reducing the operating pressure of the lock-up clutch in the fluid coupling including the lock-up clutch.
[0008]
[Means for Solving the Problems]
According to the present invention, in order to solve the main technical problem,
“ A casing connected to an input shaft driven by an engine; a pump disposed opposite to the casing and attached to the casing; a chamber formed by the pump and the casing opposite the pump; A fluid coupling having a turbine mounted on an output shaft disposed and disposed on the same axis as the input shaft;
A fluid coupling device comprising: an outer chamber formed by the casing and the turbine; and a working fluid circulation means for circulating the working fluid in the reserve tank through the working chamber formed by the pump and the turbine.
The working fluid circulation means bypasses the fluid pressure working source, a fluid pressure working source that pumps the working fluid in the reserve tank, a working fluid path that communicates the fluid pressure working source and the external chamber, and the fluid pressure working source. Switching means for switching the external chamber to communicate with the reserve tank,
When the engine is idling, the switching means is switched to bypass the fluid pressure operating source so that the external chamber communicates with the reserve tank, and the working fluid in the reserve tank is rotated by the rotation of the pump of the fluid coupling. Is circulated from the working chamber to the reserve tank through the external chamber.
A fluid coupling device is provided.
[0009]
In order to solve the above other technical problems, the fluid coupling of the fluid coupling device is arranged in an “outer chamber formed by the casing and the turbine, and an outer chamber is formed between the casing and the casing. And a lock-up clutch that has a clutch disk that forms an inner chamber with the turbine and that engages the casing and the turbine by a fluid pressure difference between the outer chamber and the inner chamber. can do.
In this case, “the working fluid circulation means includes a connection switching means for switching the fluid pressure source to communicate with the working chamber and to switch the outer chamber of the outer chamber to the reserve tank. When the lock-up clutch is engaged, the connection switching means is switched, and the working fluid is sequentially passed through the working chamber, the inner chamber, and the outer chamber by the fluid pressure operating source. It is preferable to adopt a configuration that “circulates in the reserve tank”.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of a fluid coupling device constructed according to the present invention will be described in more detail with reference to the accompanying drawings.
[0011]
FIG. 1 shows an embodiment of a drive device in which a fluid coupling device constructed according to the present invention is disposed between an automobile engine and a friction clutch. The drive device in the illustrated embodiment is constituted by an internal combustion engine 2 as a prime mover, a fluid coupling device 4 and a friction clutch 8 configured according to the present invention. The internal combustion engine 2 is a diesel engine in the illustrated embodiment, and a pump side (to be described later) of the fluid coupling device 4 is attached to the end of the crankshaft 21.
[0012]
The fluid coupling device 4 is disposed in a fluid coupling housing 40 attached to a housing 22 attached to the diesel engine 2 by fastening means such as a bolt 23. The fluid coupling device 4 in the illustrated embodiment includes a fluid coupling 400 having a casing 41, a pump 42, and a turbine 43.
[0013]
The casing 41 is mounted on the outer peripheral portion of the drive plate 44 whose inner peripheral portion is mounted on the crankshaft 21 by bolts 24 by fastening means such as bolts 441 and nuts 442. A starting ring gear 45 that meshes with a drive gear of a starter motor (not shown) is mounted on the outer periphery of the drive plate 44.
[0014]
The pump 42 is disposed to face the casing 41. The pump 42 includes a bowl-shaped pump shell 421 and a plurality of impellers 422 arranged radially in the pump shell 421. The pump shell 421 is attached to the casing 41 by means of fixing such as welding. It is attached. Therefore, the pump shell 421 of the pump 42 is connected to the crankshaft 21 via the casing 41 and the drive plate 44. For this reason, the crankshaft 21 functions as an input shaft of the fluid coupling device 4.
[0015]
The turbine 43 is disposed so as to face the pump 42. The turbine 43 includes a bowl-shaped turbine shell 431 disposed to face the pump shell 421 of the pump 42, and a plurality of runners 432 disposed radially in the turbine shell 431. . The turbine shell 431 is attached to a turbine hub 47 that is spline-fitted to an output shaft 46 that is disposed on the same axis as the crankshaft 21 as the input shaft by fixing means such as welding.
[0016]
The fluid coupling device 4 in the illustrated embodiment has working fluid circulation means for circulating working fluid from an outer chamber 400 a formed by the casing 41 and the turbine 43 through a working chamber 4 a formed by the pump 42 and the turbine 43. 6 is provided. The working fluid circulating means 6 includes a hydraulic pump 60 as a fluid pressure operating source. The hydraulic pump 60 is attached to the fluid coupling housing 40 by a fixing means such as a bolt 61 and disposed in the pump housing 62. The hydraulic pump 60 is configured to be rotationally driven by a pump hub 48 attached to the pump shell 421 of the pump 42. The pump hub 48 is rotatably supported by a bearing 490 on a cylindrical support portion 620 of a pump housing 62 that is formed so as to surround the output shaft 46. Further, as shown in FIGS. 2 and 3, a working fluid passage 460 is provided in the output shaft 46 in relation to the working fluid circulation means 6, and between the output shaft 46 and the cylindrical support portion 620. A working fluid passage 461 is provided. One end of the passage 460 opens to the left end surface in the drawing of the output shaft 46 and communicates with the external chamber 400 a formed by the casing 41 and the turbine 43, and the other end opens to the outer peripheral surface of the output shaft 46. In communication with the radial passage 462. The passage 461 is configured to communicate between the working chamber 4 a formed by the pump 42 and the turbine 43 and a communication hole 621 provided in the cylindrical support portion 620.
[0017]
Next, an embodiment of the working fluid circulation means 6 will be described with reference to the hydraulic circuit shown in FIGS.
The working fluid circulation means 6 includes a reserve tank 65 that stores the working fluid, and the working fluid in the reserve tank 65 is discharged into the passage 661 by the hydraulic pump 60. The working fluid discharged to the passage 661 is supplied to the passage 662 communicating with the passage 642 via the electromagnetic switching valve 67 (V1). When the electromagnetic switching valve 67 (V1) is in a deenergized (OFF) state as shown in FIG. 2, the passage 661 and the passage 662 are in communication with each other, and when energized (ON), as shown in FIG. The passage between the passage 661 and the passage 662 is blocked, and the passage 662 is communicated with the reserve tank 65 via the passage 663. Therefore, when the electromagnetic switching valve 67 (V1) is de-energized (OFF), the working fluid discharged to the passage 661 by the hydraulic pump 60 is the passage 662, the passage 462, and the passage 460 as indicated by arrows in FIG. These are circulated to the reserve tank 65 through the external chamber 400 a formed by the casing 41 and the turbine 43, the working chamber 4 a formed by the pump 42 and the turbine 43, the passage 461, the communication hole 621, and the passage 664. On the other hand, when the electromagnetic switching valve 67 (V1) is energized (ON), the communication between the passage 661 and the passage 662 is cut off as shown in FIG. The fluid is returned to the reserve tank 65 via a relief valve 68 provided in a relief passage 665 connecting the passage 661 and the reserve tank 65. The relief valve 68 has a valve opening pressure set at, for example, 6 kg / cm ^{2. When} the working fluid pressure in the passage 661 exceeds 6 kg / cm ² , the working fluid is returned to the reserve tank 65 through the relief passage 665. In the state shown in FIG. 3 in which the electromagnetic switching valve 67 (V1) is energized (ON), the working fluid discharged from the hydraulic pump 60 is not supplied to the fluid coupling 400. The working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 is discharged to the external chamber 400a side formed by the casing 41 and the turbine 43 by centrifugal force, and the passage 460, the passage 462, the passage 662, and the passage Since the hydraulic pump 60 is bypassed and returned to the reserve tank 65 through 663 , the inside of the working chamber 4a becomes negative pressure. That is, the fluid coupling 400 functions as a pump by rotating, and sucks the working fluid in the reserve tank 65 through the passage 664, the communication hole 621, and the passage 461 communicating with the working chamber 4a. The working fluid circulation means 6 is configured as described above. In the illustrated embodiment, the passage 661, the passage 662, the passage 462, and the passage 460 constitute a first working fluid path that communicates with the external chamber 400a. The passage 664, the communication hole 621, and the passage 461 constitute a second working fluid path that communicates the working chamber 4a and the reserve tank 65.
[0018]
The fluid coupling device 4 in the illustrated embodiment includes a control unit 100 that controls the electromagnetic switching valve 67 of the working fluid circulation unit 6. The control means 100 is constituted by a microcomputer, and is a central processing unit (CPU) 101 that performs arithmetic processing in accordance with a control program, a read-only memory (ROM) 102 that stores a control program, and a read / write that stores arithmetic results and the like. A random access memory (RAM) 103, an input interface 104, and an output interface 105. Detection signals from the vehicle speed detection sensor 111 that detects the traveling speed of the vehicle, the accelerator sensor 112 that detects the amount of depression of the accelerator pedal, and the like are input to the input interface 104 of the control unit 100 configured as described above. Further, a control signal is output from the output interface 105 to the electromagnetic switching valve 67 (VI).
[0019]
Next, the friction clutch 8 will be described with reference to FIG.
The friction clutch 8 is disposed in a clutch housing 80 attached to the fluid coupling housing 40 by bolts 81. The friction clutch 8 in the illustrated embodiment includes a clutch drive plate 82 mounted on the output shaft 46 of the fluid coupling, and a transmission shaft 83 (in the illustrated embodiment, disposed on the same axis as the output shaft 46). An input shaft of a transmission (not shown), a driven plate 86 attached to a clutch hub 84 that is spline-fitted to the transmission shaft 83 and having a clutch facing 85 mounted on the outer periphery thereof, and the driven plate 86 as a clutch drive plate. A pressure plate 87 that presses against the pressure plate 82; a diaphragm spring 88 that urges the pressure plate 87 toward the clutch drive plate 82; Release bearing 89 operating as 881 , And a clutch release fork 90 that allowed to actuate the release bearing 89 in the axial direction. In the friction clutch 8 configured as described above, in the illustrated state, the pressure plate 87 is pressed toward the clutch drive plate 82 by the spring force of the diaphragm spring 88, and therefore, the clutch facing attached to the driven plate 86. Power transmitted to the output shaft 46 of the fluid coupling by being pressed by the clutch drive plate 82 is transmitted to the transmission shaft 83 through the clutch drive plate 82 and the driven plate 86. In order to cut off this power transmission, hydraulic pressure is supplied to a slave cylinder (not shown) to operate the clutch release fork 90, and when the release bearing 89 is moved to the left in FIG. 1, the diaphragm spring 88 is shown by a two-dot chain line in the figure. By operating as shown and releasing the pressing force on the pressure plate 87, power transmission from the clutch drive plate 82 to the driven plate 86 is interrupted.
[0020]
The drive device equipped with the fluid coupling device 4 in the illustrated embodiment is configured as described above, and the operation thereof will be described below with reference to the drag torque control flowchart shown in FIG.
First, in step S1, the control means 100 checks whether or not the vehicle traveling speed (V) is zero (0), that is, whether or not the vehicle is stopped, based on the detection signal from the vehicle speed detection sensor 111. If the vehicle speed (V) is not zero (0) in step S1, the control means 100 determines that the vehicle is traveling and that it is not necessary to perform drag torque control, and proceeds to step S2 to turn on the electromagnetic switching valve 67 (V1). De-energize (OFF). When the electromagnetic switching valve 67 (V1) is de-energized (OFF), as described above, the working fluid discharged to the passage 661 by the hydraulic pump 60 is circulated in the direction indicated by the arrow in FIG. In this state, the driving force generated on the crankshaft 21 (input shaft) of the diesel engine 2 is transmitted to the casing 41 of the fluid coupling 400 via the drive plate 44. Since the casing 41 and the pump shell 421 of the pump 42 are integrally formed, the pump 42 is rotated by the driving force. When the pump 42 rotates, the working fluid in the pump 42 flows toward the outer periphery along the impeller 422 by centrifugal force, and flows into the turbine 43 side as indicated by an arrow. The working fluid that has flowed into the turbine 43 flows toward the center and returns to the pump 42 as indicated by an arrow. As described above, the working fluid in the working chamber 4a formed by the pump 42 and the turbine 43 circulates in the pump 42 and the turbine 43, so that the driving torque on the pump 42 side is transferred to the turbine 43 side via the working fluid. Communicated. The driving force transmitted to the turbine 43 side is transmitted to the output shaft 46 through the turbine shell 431 and the turbine hub 47 and further transmitted to the transmission (not shown) through the friction clutch 8.
[0021]
When the vehicle speed (V) is zero (0) in step S1, the control means 100 proceeds to step S3 and the accelerator pedal depression amount (AP) is zero (0), based on the detection signal from the accelerator sensor 112. Check whether the accelerator pedal is released. If it is determined in step S3 that the accelerator pedal depression amount (AP) is not zero (0), the control means 100 determines that the engine is not idling and it is not necessary to perform drag torque control, and the process proceeds to step S2 and the electromagnetic switching valve. 67 (V1) is de-energized (OFF). In step S3, if the accelerator pedal depression amount (AP) is zero (0), that is, if the accelerator pedal is released, the control means 100 determines that the engine is idling and that it is necessary to perform drag torque control. In step S4, the electromagnetic switching valve 67 (V1) is energized (ON). When the electromagnetic switching valve 67 (V1) is energized (ON), the communication between the passage 661 and the passage 662 is cut off as shown in FIG. 3, and the passage 662 is communicated with the reserve tank 65 via the passage 663. . Accordingly, the working fluid discharged to the passage 661 by the hydraulic pump 60 is returned to the reserve tank 65 through the relief valve 68. On the other hand, as described above, the fluid coupling 400 functions as a pump by its own rotation, discharges the working fluid in the working chamber 4a to the external chamber 400a side by centrifugal force, and passes through the passage 664, the communication hole 621, and the passage 461. Then, the working fluid in the reserve tank 65 is sucked. Then, the working fluid discharged to the external chamber 400a side is returned to the reserve tank 65 by bypassing the hydraulic pump 60 through the passage 460, the passage 462, the passage 662, and the passage 663. Thus, in the illustrated embodiment, when the electromagnetic switching valve 67 (V1) is energized (ON), the working fluid discharged from the hydraulic pump 60 is not circulated to the fluid coupling 400, but the fluid coupling 400 itself. Since the working fluid is circulated by the pumping action caused by the rotation of the hydraulic fluid, the charging efficiency of the working fluid into the fluid coupling 400 is lowered, so that the drag torque is greatly reduced.
[0022]
As described above, the electromagnetic switching valve 67 (V1) is energized (ON) in order to reduce the drag torque of the fluid coupling in the idling state of the engine in which the vehicle speed (V) is zero (0) and the accelerator pedal is released. If so, the control means 100 returns to step S1 so that the vehicle speed (V) is no longer zero (0) (the vehicle is in a running state) or the accelerator pedal depression amount (AP) is no longer zero (0) in step S3. If the accelerator pedal is depressed (depressed), it is determined that the engine is not idling, and the process proceeds to step S2 to deenergize (OFF) the electromagnetic switching valve 67 (V1).
[0023]
Next, another embodiment of the fluid coupling device 4 will be described with reference to FIGS.
The embodiment shown in FIGS. 5 to 8 is provided with a lockup clutch 50 for directly connecting the casing 41 and the turbine 43 to the fluid coupling device 4 shown in FIGS. Along with the addition of the up clutch 50, an electromagnetic direction control valve 70 (V2) functioning as a connection switching means is disposed in the passage 661 and the passage 664 of the working fluid circulation means 6, and other configurations are as follows. Since this embodiment is substantially the same as the embodiment shown in FIGS. 1 to 3, the same reference numerals are given to the same members, and descriptions thereof are omitted.
The lock-up clutch 50 in the embodiment shown in FIGS. 5 to 8 is disposed between the casing 41 and the turbine 43 and forms an outer chamber 40 a between the casing 41 and the inner chamber 40 b between the turbine 43. A clutch disk 51 is formed. The clutch disc 51 is supported so that the inner peripheral edge thereof can rotate relative to the outer periphery of the turbine hub 47 and can slide in the axial direction. A clutch facing 52 is provided on the outer peripheral portion of the clutch disk 51 on the surface facing the casing 41. It is installed. An annular recess 53 is formed on the outer peripheral portion of the clutch disc 51 on the inner chamber 40b side, and a plurality of damper springs 55 respectively supported by support pieces 54 are provided in the recess 53 at predetermined intervals. Arranged. On both sides of the plurality of damper springs 55, an input side retainer 56 attached to the clutch disk 51 is protruded and disposed between the damper springs 55 and attached to a turbine shell 431 of the turbine 43. Further, an output side retainer 57 is provided so as to protrude.
[0024]
The lock-up clutch 50 in the illustrated embodiment is configured as described above, and its operation will be described.
When the pressure of the working fluid on the inner chamber 40b side is higher than the pressure of the working fluid on the outer chamber 40a, that is, the working chamber 4a in which the working fluid supplied by the working fluid circulation means described later is formed by the pump 42 and the turbine 43. 1 flows from the inner chamber 40b to the outer chamber 40a, the clutch disk 51 is pressed to the left in FIG. 1, so that the clutch facing 52 mounted on the clutch disk 51 is pressed by the casing 41 and frictionally engaged. To do. Therefore, the casing 41 and the turbine 43 are directly connected to each other via the clutch facing 52, the clutch disc 51, the input side retainer 56, the damper spring 55, and the output side retainer 57. On the other hand, when the pressure of the working fluid in the outer chamber 40a is higher than the pressure of the working fluid on the inner chamber 40b side, that is, the working fluid supplied by the working fluid circulation means described later passes from the outer chamber 40a to the pump 42 through the inner chamber 40b. When circulating in the working chamber 4 a formed by the turbine 43, the clutch disk 51 is pressed rightward in FIG. 5, so that the clutch facing 52 attached to the clutch disk 51 is frictionally engaged with the casing 41. Therefore, the transmission connection between the casing 41 and the turbine 43 is released.
[0025]
The working fluid circulating means 6 in the embodiment shown in FIGS. 5 to 8 includes the passage 661 and the electromagnetic directional control valve 70 (V2) disposed in the passage 664 of the working fluid circulating means 6 shown in FIGS. It has. When the electromagnetic direction control valve 70 (V2) is deenergized (OFF), as shown in FIGS. 6 and 7, the electromagnetic direction control valve 70 (V2) is connected to the passage 661a connected to the hydraulic pump 60 and the electromagnetic switching valve 67 (V1). The passage 661 b communicates with the passage 664 a communicated with the communication passage 621 and the passage 664 b connected to the reserve tank 65. When the electromagnetic direction control valve 70 (V2) is energized (ON), as shown in FIG. 8, the passage 661a and the passage 664b communicate with each other, and the passage 661b and the passage 664b communicate with each other. The electromagnetic switching valve 67 (V1) and the electromagnetic direction control valve 70 (V2) are controlled by the control means 100 in the embodiment shown in FIGS.
[0026]
The fluid coupling device in the embodiment shown in FIGS. 5 to 8 is configured as described above, and the operation thereof will be described below.
First, a state in which the diesel engine 2 is operated at a rotational speed equal to or higher than idling rotation and the driving torque is transmitted by the fluid coupling will be described. In this case, the electromagnetic direction control valve 70 (V2) of the working fluid circulation means 6 is de-energized (OFF) and the electromagnetic switching valve 67 (V1) is de-energized (OFF). 6 is circulated in the direction indicated by the arrow. The state shown in FIG. 6 is the same as that of the embodiment shown in FIG. That is, when the casing 41 and the pump 42 are rotated by the crankshaft 21 (input shaft) of the diesel engine 2, the working fluid in the pump 42 flows toward the outer periphery along the impeller 422 by centrifugal force, as indicated by the arrows. Then, it flows into the turbine 43 side and the driving torque on the pump 42 side is transmitted to the turbine 43 side via the working fluid. The driving force transmitted to the turbine 43 side is transmitted to the output shaft 46 through the turbine shell 431 and the turbine hub 47 and further transmitted to the transmission (not shown) through the friction clutch 8. When the working fluid is circulated in the direction indicated by the arrow in FIG. 6, the clutch disc 51 is pressed to the right in FIGS. 5 and 6 as described above. The transmission connection between 41 and the turbine 43 is released.
[0027]
Next, a state where the diesel engine 2 is idling will be described. In this case, as shown in FIG. 7, the electromagnetic direction control valve 70 (V2) of the working fluid circulation means 6 is deenergized (OFF) and the electromagnetic switching valve 67 (V1) is energized (ON). ) When the electromagnetic switching valve 67 (V1) is energized (ON), the communication between the passage 661b and the passage 662 is cut off as shown in FIG. 7, and the passage 662 is communicated with the passage 663. Therefore, the working fluid discharged to the passage 661a by the hydraulic pump 60 and flowing to the passage 661b through the electromagnetic direction control valve 70 (V2) is returned to the reserve tank 65 through the relief valve 68. On the other hand, as described above, the fluid coupling 400 functions as a pump by its rotation, discharges the working fluid in the working chamber 4a to the inner chamber 40b side by centrifugal force, and passes through the passage 664, the communication hole 621, and the passage 461. Then, the working fluid in the reserve tank 65 is sucked. The working fluid discharged to the inner chamber 40b is returned to the reserve tank 65 through the outer chamber 40a, the passage 460, the passage 462, the passage 662, and the passage 663. Thus, in the illustrated embodiment, when the electromagnetic switching valve 67 (V1) is energized (ON), the working fluid discharged from the hydraulic pump 60 is not circulated to the fluid coupling 400, but the fluid coupling 400 itself. Since the working fluid is circulated by the pumping action caused by the rotation of the hydraulic fluid, the charging efficiency of the working fluid into the fluid coupling 400 is lowered, so that the drag torque is greatly reduced. At this time, the working fluid passes through the working chamber 4a and flows from the inner chamber 40b to the outer chamber 40a, but the lockup clutch 50 is not actuated because the pressure of the working fluid is low.
[0028]
Next, a state in which the lockup clutch 50 is operated to directly connect the casing 41 and the turbine 43 to transmit drive torque will be described. In this case, the electromagnetic direction control valve 70 (V2) of the working fluid circulation means is energized (ON) and the electromagnetic switching valve 67 (V1) is deenergized (OFF). It is circulated in the direction indicated by the arrow. Therefore, as described above, the pressure of the working fluid on the inner chamber 40b side is higher than the pressure of the working fluid on the outer chamber 40a side, and the clutch disk 51 is pressed to the left in FIGS. The attached clutch facing 52 is pressed against the casing 41 and frictionally engaged. Therefore, the casing 41 and the turbine 43 are directly connected to each other via the clutch facing 52, the clutch disc 51, the input side retainer 56, the damper spring 55, and the output side retainer 57. Accordingly, the driving force generated on the crankshaft 21 (input shaft) of the diesel engine 2 is transmitted to the output shaft 46 via the drive plate 44, the casing 41, the lockup clutch 50, the turbine 43, and the turbine hub 47, and further, It is transmitted to a transmission (not shown) via the friction clutch 8. In the illustrated embodiment, since the drag torque can be reduced as described above, it is not necessary to lower the supply pressure of the working fluid in order to reduce the drag torque, resulting in insufficient operating pressure of the lockup clutch. There is nothing.
[0029]
【The invention's effect】
Since the fluid coupling device according to the present invention is configured as described above, the following effects can be obtained.
[0030]
That is, in the fluid coupling device according to the present invention, the working fluid circulation means for circulating the working fluid connects the first working fluid path communicating with the external chamber of the fluid coupling, the working chamber of the fluid coupling, and the reserve tank. A second working fluid path, a fluid pressure source that discharges the working fluid in the reserve tank to the first working fluid path, and switching means disposed in the first working fluid path, Since the switching means is configured to selectively operate in a state in which the external chamber communicates with the fluid pressure operating source and a state in which the external chamber communicates with the reserve tank, the idling operation of the engine that drives the fluid coupling is performed. Sometimes, the fluid coupling functions as a pump by its own rotation by communicating the external chamber to the reserve tank by the switching means. For this reason, since the filling efficiency of the working fluid into the fluid coupling is lowered, the drag torque can be greatly reduced. Therefore, the idling operation of the engine becomes smooth, the occurrence of abnormal vibration can be prevented, and the fuel consumption during the idling operation can be improved.
[0031]
In addition, according to the present invention, as described above, the drag torque can be reduced without reducing the fluid pressure of the working fluid circulated through the fluid coupling. Therefore, in the fluid coupling including the lockup clutch, the lockup clutch There is no shortage of operating pressure.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a drive device equipped with a fluid coupling device constructed according to the present invention.
FIG. 2 is a diagram illustrating an operating state of a working fluid circulation unit of the fluid coupling device illustrated in FIG.
FIG. 3 is a diagram illustrating an operating state of a working fluid circulation unit of the fluid coupling device illustrated in FIG. 1 and is an explanatory diagram of an operating state during an idling operation of an engine that drives the fluid coupling;
FIG. 4 is a flowchart showing an operation of drag torque control of a control means provided in the fluid coupling device shown in FIG. 1;
FIG. 5 is a cross-sectional view showing another embodiment of a drive device equipped with a fluid coupling device constructed according to the present invention.
6 is a diagram illustrating an operating state of a working fluid circulation unit of the fluid coupling device illustrated in FIG. 5 and is an explanatory diagram of a state in which driving torque is transmitted by the fluid coupling.
7 is a diagram illustrating an operating state of a working fluid circulation unit of the fluid coupling device illustrated in FIG. 5, and is an explanatory diagram of an operating state during an idling operation of an engine that drives the fluid coupling.
FIG. 8 is an explanatory view showing the operating state of the working fluid circulating means of the fluid coupling device shown in FIG. 5, in a state where the lock-up clutch is operated.
[Explanation of symbols]
2: Internal combustion engine 21: Crankshaft 4: Fluid coupling device 40: Fluid coupling housing 41: Casing 42: Pump 400: Fluid coupling 421: Pump shell 422: Impeller 43: Turbine 431: Turbine shell 432: Runner 44: Drive plate 45 : Ring gear 46: Output shaft 47: Turbine hub 48: Pump hub 50: Lockup clutch 51: Clutch disc 52: Clutch facing 55: Damper spring 56: Input side retainer 57: Output side retainer 6: Working fluid circulation means 60: Hydraulic pump 62: Pump housing 65: Reserve tank 67: Electromagnetic switching valve (V1)
68: Relief valve 70: Electromagnetic direction control valve (V2)
8: Friction clutch 80: Clutch housing 82: Clutch drive plate 83: Transmission shaft 84: Clutch hub 85: Clutch facing 86: Driven plate 87: Pressure plate 88: Diaphragm spring 89: Release bearing 90: Clutch release fork 100: Control means 111: Vehicle speed detection sensor 112: Accelerator sensor

Claims (3)

A casing connected to an input shaft driven by an engine, a pump disposed opposite to the casing and attached to the casing, and a chamber formed by the pump and the casing disposed opposite the pump. A fluid coupling having a turbine attached to an output shaft disposed on the same axis as the input shaft;
A fluid coupling device comprising: an outer chamber formed by the casing and the turbine; and a working fluid circulation means for circulating the working fluid in the reserve tank through the working chamber formed by the pump and the turbine.
The working fluid circulation means bypasses the fluid pressure working source, a fluid pressure working source that pumps the working fluid in the reserve tank, a working fluid path that communicates the fluid pressure working source and the external chamber, and the fluid pressure working source. Switching means for switching the external chamber to communicate with the reserve tank,
When the engine is idling, the switching means is switched to bypass the fluid pressure operating source so that the external chamber communicates with the reserve tank, and the working fluid in the reserve tank is rotated by the rotation of the pump of the fluid coupling. Is circulated from the working chamber to the reserve tank through the external chamber . The fluid coupling has a clutch disk which is disposed in an outer chamber formed by the casing and the turbine and forms an outer chamber between the casing and an inner chamber between the turbine and The fluid coupling device according to claim 1, further comprising a lock-up clutch that engages the casing and the turbine by a fluid pressure difference between the outer chamber and the inner chamber. The working fluid circulation means is provided with connection switching means for switching the fluid pressure source to communicate with the working chamber and to switch the outer chamber of the outer chamber to the reserve tank. When the lockup clutch is brought into contact, the connection switching means is switched, and the working fluid is circulated to the reserve tank through the working chamber, the inner chamber and the outer chamber in order by the fluid pressure operating source. Item 3. The fluid coupling device according to Item 2.

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